The present invention relates to an actuator for loading/unloading a slider in a magnetic disk apparatus, a floppy disk apparatus or the like, and more particularly, to an actuator for loading/unloading a slider which permits the slider to land on a disk surface extremely smoothly.
A typical conventional floating head slider generally effects a stable floating on the order of about 0.2 .mu.m from a disk surface when rotating at a constant speed. The greatest technical problem of this slider is to avoid any crush thereof on the disk surface. The slider is required to have a high reliability, particularly in its operation in a non-stationary state, such as the landing thereof. In order to meet this need, such a driving unit of a means for loading/unloading the slider has been proposed as employing a shape memory alloy member. In such a structure, however, it is difficult to apply a constant pressing force to the slider, since the slider equipped with a magnetic head and the shape memory alloy member operate as one unit. In addition, since the driving force derived from the shape memory alloy member is directly applied against the resilient force of a pressing member supporting the slider, it is not possible to largely change the pressing force and the resilient force derived through the deformation of the shape memory alloy member, so that the motion is unstable and the operating speed is low, disadvantageously.